A reexamination of the Kitajima and Butler (1975) model for relating chlorophyll a fluorescence to photochemistry

The main assumptions of the well-known Kitajima and Butler (1975) model, describing the relationship between the ratio of the maximum variable chlorophyll <i>a</i> fluorescence to the maximum fluorescence (F_V/F_M) and the photochemical quantum yield of PSII (Φ_Po), have been analyzed. Using the experimental data from the literature, potential "weak points" of this model are discussed, as well as the reasons for the differences between the F_V/F_M values and the actual Φ_Po values. Special attention is focused on the fluorescence measurement procedures using the saturating single turnover light flashes and the saturating multiple turnover light pulses. It is concluded that if the F_V/F_M measurements are made properly, the value of Φ_Po can indeed be estimated.